地震是一种严重的自然灾害。为预测预防地震灾害,首先要确定哪些地方有可能发生破坏性地震,然后按危险程度分为若干个区域,在不同的区域内采取不同的抗震设防标准,这个过程就是地震区划。因为地震区划图常采用小比例尺,所提供的地震危险程度是平均值,不能反映由于局部场地条件的影响而产生的地震破坏在小范围内的差异。而要考虑这种差异,按具体地点的场地条件,给特定工程场地的抗震设计提供依据,就产生和发展了地震小区划。 Earthquake is a serious natural disaster. In order to predict and prevent earthquakes, we must first determine where the devastating earthquakes are likely to occur and then divide them into several regions according to the degree of danger. Different seismic fortification standards are adopted in different regions. This process is the seismic zoning. Because seismic zoning maps often use small scales, the degree of seismic hazard provided is an average and does not reflect small differences in seismic damage due to local site conditions. Considering this difference, according to the site conditions of a specific site, it provides a basis for the aseismic design of a specific project site, thus creating and developing a sub-project of the earthquake.